Concrete insert



FIG. 1 is a front elevational view of a concrete insert showing my new design, the rear elevational view being identical;

FIG. 2 is a left side elevational view thereof, the right side elevational view being identical;

FIG. 3 is a top plan view thereof; and,

FIG. 4 is a bottom plan view thereof. 

The ornamental design for a concrete insert, as shown and described. 